Snake Venom Proteinases as Toxins and Tools

Abstract

Proteinases from snake venoms have long been fascinating targets due to their structural, functional, and domain architectural diversities. Depending on these differences, snake venom proteinases are broadly classified as snake venom serine proteinases (SVSPs) and snake venom metalloproteinases (SVMPs). Unlike SVSPs, additional domains along with catalytic domain present in SVMPs are responsible for the subclassification. Non-catalytic domains of SVMPs direct catalytic domain to site-specific target and thereby assist to amplify the toxicities associated. The presence of additional domains along with catalytic domain renders SVMPs more toxic than SVSPs. Though non-catalytic domains function to facilitate the site-specific action of SVMPs, catalytic domain with the metal ion zinc in the active site is critical in eliciting the toxic action. Despite having a lot of reports regarding the toxic action of SVMPs and SVSPs, they prove to be promising tools when studied individually. In many cases their isolation and characterization have led to pharmacologically active drugs or research/diagnostic tool. This chapter initially describes the SVMP-induced local tissue damage such as hemorrhage and its neutralization by employing a novel strategy; zinc specific chelation therapy. Secondly, venom proteinase-induced systemic alterations such as perturbations in the complement and hemostatic system along with their applications as tools in the similar area are discussed. Finally, diagnostic applications of both SVSPs and SVMPs in coagulation laboratories and also their use in the identification of the snake species responsible for bite are discussed.